Test

We need a way to tell that what we’ve been writing so far is correct. Testing is straightforward in Rust. We don’t need to create a separate test file. Right at the bottom of quiz/src/quiz.rs, add the following:

#[cfg(test)]
mod tests {
  use super::*;

  #[test]
  fn test_question_is_answered() {
    let q = Question {
      title: String::from("Is this a question?"),
      answer: true,
      user_answer: Some(true)
    };

    assert_eq!(q.is_answered(), true);
  }

  #[test]
  fn test_question_is_correct() {
    let q = Question {
      title: String::from("Is this a question?"),
      answer: true,
      user_answer: Some(true)
    };

    assert_eq!(q.is_correct(), true);
  }
}

Read more about testing in Rust here.

To run the tests, do:

cargo test -p quiz

You’ll notice that no tests are run. That’s because quiz.rs is not being used in the project. We need to add it to main.rs. Add the following to the very top of main.rs:

mod quiz;

Now try to run the test again.

That’s not all, exercise

Surely, those two tests are not enough. Implement additional tests to cover:

• Moving to next question for a quiz
• Moving to previous question for a quiz
• Answering a question from a quiz
• Counting score